Minimally invasive procedures are desirable because such procedures can reduce pain and provide relatively quick recovery times as compared with conventional open medical procedures. Many minimally invasive procedures are performed with an endoscope (including without limitation laparoscopes). Such procedures permit a physician to position, manipulate, and view medical instruments and accessories inside the patient through a small access opening in the patient's body. Laparoscopy is a term used to describe such an “endosurgical” approach using an endoscope (often a rigid laparoscope). In this type of procedure, accessory devices are often inserted into a patient through trocars placed through the body wall.
Still less invasive treatments include those that are performed through insertion of an endoscope through a natural body orifice to a treatment site. Examples of this approach include, but are not limited to, cystoscopy, hysteroscopy, esophagogastroduodenoscopy, and colonoscopy. Many of these procedures employ the use of a flexible endoscope during the procedure. Flexible endoscopes often have a flexible, steerable articulating section near the distal end that can be controlled by the user by utilizing controls at the proximal end.
Some flexible endoscopes are relatively small (1 mm to 3 mm in diameter), and may have no integral accessory channel (also called biopsy channels or working channels). Other flexible endoscopes, including gastroscopes and colonoscopes, have integral working channels having a diameter of about 2.0 to 3.5 mm for the purpose of introducing and removing medical devices and other accessory devices to perform diagnosis or therapy within the patient. As a result, the accessory devices used by a physician can be limited in size by the diameter of the accessory channel of the scope used. Additionally, the physician may be limited to a single accessory device when using the standard endoscope having one working channel.
Certain specialized endoscopes are available, such as large working channel endoscopes having a working channel of 5 mm in diameter, which can be used to pass relatively large accessories, or to provide capability to suction large blood clots. Other specialized endoscopes include those having two working channels. One disadvantages of such large diameter/multiple working channel endoscopes can be that such devices can be relatively expensive. Further, such large diameter/multiple working channel endoscopes can have an outer diameter that makes the endoscope relatively stiff, or otherwise difficult to intubate.
Various references describe methods or systems related to an endoscope, such as for example: U.S. Pat. No. 5,025,778, Silverstein; U.S. Pat. No. 4,947,827, Opie; US 2002/107530 published Aug. 8, 2002 in the name of Sauer; U.S. Pat. No. 6,352,503, Matsui. One disadvantage of known systems is the potential for the distal end of a device used externally of an endoscope to move, which may cause the accessory to lack precision or the ability to be maintained within a desired field of view of the imaging capability of the endoscope.
WO 00/48506 published Aug. 24, 2000 in the name of Herrmann discloses a deformable endoscope with at least one supplementary device. The unit comprising the endoscope and the supplementary device is said to have a non-round cross-section. Such a non-circular endoscope may be disadvantageous from the point of view of cost, complexity, or ease in cleaning/sterilization. For instance, a standard endoscope with a smooth, substantially-circular cross section can be relatively easy to sanitize and clean.
WO 00/48506 published Aug. 24, 2000 in the name of Kortenbach, discloses methods and devices for delivering a medical instrument over the exterior of an endoscope to allow the use of instruments too large to fit through the lumena of the endoscope. Kortenbach discloses a collar for use with an endoscope, resilient straps, a flexible sheath having a reclosable seam, flexible polymer extrusions, and a floppy tangential sheath defining a lumen having an irregular (collapsible) cross section. Kortenbach also discloses a track with an inverted T configuration.
Endoscopes may also be used with feeding tubes. For instance, it is known to advance a feeding tube through an internal channel of an endoscope. It is also known to advance a feeding tube together with an endscope, such as by holding the distal end of the feeding tube with a pair of forceps extending from a distal end of the endoscope, and “dragging” the feeding tube along the outside of the endoscope while advancing the endoscope to a desired location.
Investigators have reported that a conventional pull method of PEG placement may be supplemented with an overtube to reduce risk of peristomal infection. “Efficacy of an Overtube for Reducing the Risk of Peristomal Infection after PEG Placement: a Prospective, Randomized Comparison Study” Iruru Maetani, MD, et al., Gastrointestinal Endoscopy, Volume 61, No. 4, 2005, hereby incorporated by reference, discloses the use of an overtube during PEG placement.
Still, scientists and engineers continue to seek improved devices and methods for the introducing medical devices into the gastro-intestinal tract, including improved devices and methods for placing feeding tubes in patients.